McKinney SQ3331Square Barrel 2-Knuckle Decorative Hinge, 4-1/2" by 4-1/2"

No. The SQ3331 is built for 1-3/4 inch thick square edge doors only, so a 1-3/8 inch door (the common older interior thickness) is out of range. It also won't suit a beveled edge door. For a 1-3/8 inch opening you want a residential-weight hinge such as the Deltana DSB35 3-1/2 x 3-1/2 square hinge or the Emtek 91013 residential plain bearing pair.

Yes, handing is part of the order. The SQ3331 comes as LH (left hand) or RH (right hand), and unlike a five knuckle hinge with a symmetrical barrel, a two knuckle hinge is not reversible in the field. Stand outside the door, on the side it swings away from: hinges on your left is LH, hinges on your right is RH. Get it wrong and the barrel reads backwards on the opening.

The SQ3331 is a 4-1/2 by 4-1/2 inch full mortise hinge with square corners, so it drops into a standard square corner 4-1/2 inch prep in both leaves. If your existing doors are routed with radius corners (1/4 inch or 5/8 inch), this one won't sit right without recutting the mortise, and you'd be better off matching corner style to what is already cut.

No, not for high traffic. The SQ3331 is a standard duty commercial hinge recommended for doors of average weight at average frequency. A main entrance, a gym door, or anything on a closer in a busy building should go heavy weight instead: the Don-Jo HWBB84545 heavy weight ball bearing hinge in the same 4-1/2 by 4-1/2 size, or the Ives 3CB1HW heavy weight concealed bearing hinge.

Yes, if the door swings out. On an out-swing opening the hinge barrel is on the outside, and a standard pin can be driven out to lift the door off. The SQ3331 offers NRP (non-removable pin) as an option you select when ordering. The hinge is rated for interior or exterior use on hollow metal and wood frame doors, so out-swing exterior is exactly where NRP earns its place. Interior doors that swing into the room don't need it.

The McKinney SQ3331 cannot be electrified. For an opening that needs power carried through the hinge, the Command Access ETH-CB70 is an energy transfer hinge with 3 knuckles on a standard weight steel base, rated medium duty; the ETH-BB68 is the 5 knuckle heavy duty version in the same ETH family. The BEST CECB179-12C is a steel full mortise concealed bearing electrified hinge with a 12-wire quick connect, rated medium duty. If the opening also needs door position monitoring, the Command Access ETM-CB70 adds door position sensing on a 3 knuckle steel base and the ETM-BB68 carries an integrated door position switch on a heavy duty base.

The McKinney SQ3331 is a 4.5 inch by 4.5 inch square corner full mortise hinge with a stainless steel base. The Orca Hardware 3535 Series is also a 4-1/2 inch by 4-1/2 inch square corner commercial hinge, rated medium duty with a ball bearing function. The Deltana CSB45N is another 4-1/2 inch by 4-1/2 inch square hinge, sold as a pair with a non-removable pin. The SQ3331 differs in that it is a two knuckle hinge with a square barrel, so the barrel profile on the door edge does not match a multi-knuckle hinge even where the leaf size does.

The McKinney SQ3331 is rated standard duty and is recommended for doors of average weight with average frequency. For heavier service at the same 4-1/2 inch leaf height, the Don-Jo HWBB74545 and HWBB84545 are heavy weight full mortise ball bearing hinges in 4-1/2 inch by 4-1/2 inch with a satin chrome finish, both rated heavy duty. The Hager BB1168 is a full mortise ball bearing heavy duty hinge furnished with a non-removable pin. The Ives 3CB1HW is a steel heavy weight concealed bearing full mortise hinge with 3 knuckles, also heavy duty.

Knuckle count is the look. The SQ3331 is a two knuckle hinge with a square barrel, so the exposed edge reads as two clean segments rather than the banded five knuckle pattern, which is why it gets specified on architectural and hospitality openings where the hardware is visible. Function is otherwise conventional full mortise. A standard commercial five knuckle in the same 4-1/2 by 4-1/2 size is the Stanley FBB191 full mortise standard weight hinge; a three knuckle concealed bearing option is the Ives 3CB1.

The SQ3331 bearing contains an anti-friction component, which is what keeps a two knuckle hinge swinging smoothly instead of running metal on metal like a plain bearing hinge. That said, it is rated for average frequency use. For openings cycling constantly, step up to a ball bearing hinge such as the Orca Hardware 3535 Series 4-1/2 by 4-1/2 square corner ball bearing commercial hinge.

The SQ3331 has a stainless steel base material, which holds up better in damp and salt-air conditions than a plated steel hinge, and it is rated for exterior as well as interior openings on hollow metal and wood frames. The finish offered is 613 satin bronze oil-rubbed, a living finish that will darken and wear at the touch points over time.

Physically yes on a matching opening, since the SQ3331 is a 4-1/2 by 4-1/2 square corner full mortise hinge on 1-3/4 inch square edge doors, which is the same prep most commercial steel and wood doors already carry. Visually no. The two knuckle square barrel does not match a five knuckle barrel on the next door down the hall, so if appearance matters, change out the whole opening or the whole run rather than one leaf.

No. The McKinney SQ3331 is a commercial hinge in a 4.5 inch by 4.5 inch size with a stainless steel base. Residential square corner hinges run smaller and lighter: the Emtek 91013 is a residential plain bearing pair at 3-1/2 inch by 3-1/2 inch with square corners in plated steel, the Schlage Residential S3P1010 is a 3.5 inch by 3.5 inch square corner plain bearing mortise hinge sold three to a pack, and the Ives 1010RP is a steel plain bearing residential hinge with square corners in a set of three. The Deltana DSB35 is a 3-1/2 inch by 3-1/2 inch residential square hinge pair and the DSB3 is 3 inch by 3 inch. None of those match the 4-1/2 inch leaf height, so the mortise in the frame and door will not line up.

The McKinney SQ3331 is a full mortise hinge, mortised into both the door and the frame. Where the frame will not take a mortise, the Hager 1129 is a half mortise plain bearing commercial hinge at 4-1/2 inch standard weight steel, and the Hager 990 STEEL is a full surface prison hinge 3 inch by 4 inch with a welded tip. Half mortise and full surface hinges prep differently at the frame, so they are not drop-in for a full mortise opening.

The Stanley Security FBB191 is a 5-knuckle full mortise standard weight hinge at 4.5 inch by 4.5 inch, matching the 4.5 inch by 4.5 inch size of the McKinney SQ3331. The SQ3331 is a two knuckle hinge with a square barrel and square corners on a stainless steel base, so the FBB191 matches the leaf dimension but presents a five knuckle barrel at the door edge instead of the two knuckle decorative profile.

The McKinney SQ3331 is a standard duty decorative hinge for interior or exterior hollow metal and wood frame doors of average weight. Detention openings take a different hinge entirely: the BEST BB855 is a heavy-duty steel double weight concealed ball bearing prison hinge in the Detention Hardware series, the Stanley Security BB855 is a double weight prison hinge at 5 inch by 6 inch furnished with no holes and not swaged, and the Hager 990 STEEL is a full surface prison hinge 3 inch by 4 inch with a welded tip, rated heavy duty. For a security opening that still wants a conventional leaf, the Deltana DE44R5TA is a 4 inch by 4 inch security hinge with a 5/8 inch radius in steel, sold as a pair.

No. The McKinney SQ3331 is for 1-3/4 inch thick square edge doors only. Where the door edge is radiused rather than square, the Orca Hardware 4014 Series is a 4 inch by 4 inch quarter inch radius corner plain bearing commercial hinge and the 3514 Series is the 3.5 inch by 3.5 inch quarter inch radius version, both medium duty. The Delaney RH45xx is a 4 inch by 4 inch exterior residential hinge pair with a 5/8 inch radius, and the RH35xx is the 3-1/2 inch by 3-1/2 inch bulk steel interior version with the same 5/8 inch radius.

The McKinney SQ3331 can be ordered with the NRP non-removable pin option. The Hager BB1168 is furnished as a non-removable pin full mortise ball bearing heavy duty hinge, and the Deltana CSB45N is a 4-1/2 inch by 4-1/2 inch square hinge pair supplied with a non-removable pin. NRP matters on an out-swinging exterior door where the barrel is exposed on the outside face.

The McKinney SQ3331 is a full mortise hinge for interior or exterior hollow metal and wood frame doors swinging one way. A door that swings both directions takes a pivot instead: the BEST DAP-3 is a heavy duty double acting pivot for commercial interior doors, rated heavy duty in the Emergency Rescue Hardware series. The BEST CB1969R is a concealed bearing heavy weight pivot-reinforced hinge, rated heavy duty, for openings where the door is pivot hung but still carries hinges.

Commercial. The SQ3331 is a standard duty commercial full mortise hinge for hollow metal and wood frame doors. If you're doing residential interior doors, the 3-1/2 by 3-1/2 sizes are the usual fit, and the Delaney RH35xx bulk interior residential hinges or the Schlage Residential S3P1010 square corner mortise hinges (pack of three) are the right shelf for that job.

The McKinney SQ3331 is a two knuckle hinge with a square barrel, stainless steel base, rated standard duty. The Ives 3CB1 is a steel 3-knuckle concealed bearing full mortise hinge rated medium duty, and the 3CB1-B is the same 3-knuckle concealed bearing full mortise hinge in a medium duty commercial grade. The Stanley CECB1900R54L is a three knuckle concealed bearing steel full mortise hinge, standard weight, 4-1/2 inch by 4-1/2 inch with square corners, left-handed and 4-wire. The knuckle count changes the look of the barrel on the door edge as well as the bearing arrangement.